Automatic capping of containers is common in many industries. One type of capping machine used to perform the capping process screws a threaded cap on a threaded container having a threaded finish. To that effect, the capping machine may advance the containers with a conveyor. At some point along the conveyor, a cap is positioned above the container and the cap and conveyor assembly subsequently moves to a capping head. For example, the capping head includes a pair of belts moving at different speeds between which the cap moves. The belts move one side of the cap faster than the other side, due to their speed differential, which screws the cap as the container advances along the conveyor.
A common problem in such automatic capping is cross-threading. This problem occurs when the cap tilts when the threads of the finish are engaged by the threads of the cap. As a result, the cap is cocked and the container is not hermetically sealed by the cap. To prevent distribution of such problematic containers, there is a need to inspect all containers coming out of the capping machine and to reject cross-threaded containers, which are either disposed or otherwise handled. These operations require either the use of relatively expensive machines and inspection systems, or of additional employees.
Accordingly, there exists a need for an improved capping machine. It is a general objective of the present invention to provide such a capping machine.